In recent years, the presence of various enantiomers has been confirmed within the bodies of higher order animals such as mammals, and the important functions that each enantiomer serves are being elucidated. Among amino acids, large amounts of L-amino acids are present inside a body as constituents of proteins or nutrient sources whereas trace amounts of D-amino acids that are enantiomers thereof are frequently present inside the body. Because of this, when D-amino acids are analyzed, interference from a wide variety of peptides or amino compounds frequently occurs. Furthermore, mass spectrometry used for analysis at a high resolution is such that separation of enantiomers is impossible in principle, and hence, development of an optical resolution technique at a high resolution is desired to conduct accurate quantitative analysis.
Non-Patent Document 1 discloses a method for optically resolving fluorescently derivatized amino acids by using SUMICHIRAL (registered trademark) OA2500S (produced by Sumika Chemical Analysis Service, Ltd.).
Patent Document 1 discloses a two-dimensional HPLC wherein a column for optical resolution is combined with a reversed-phase column.
However, in addition to the elution order of D-bodies and L-bodies of amino acids not being identical, there is a problem of a low resolution between peaks originating from the D-bodies and peaks originating from the L-bodies.